This invention relates to nozzles, and more particularly to pin-jet nozzles capable of producing fog in evaporative cooling systems and the like.
Evaporative cooling systems have been employed in various applications for a number of years. Such systems typically involve a pressurized fluid, usually water, escaping through a small orifice and impinging on a proximate surface. The force of the pressurized stream against the proximate surface causes the fluid to disperse into minute particles creating a localized fog. A fog differs from a mist, although the terms are often used imprecisely. As used herein, a fog contains small droplets which evaporate from the air rather than falling to cause a localized wetting. Fogs are typically used for cooling, and sometimes, for humidification. A mist, as used herein, contains larger particles which fall to create a localized wetting, and are typically used more for providing irrigation.
A pin-jet nozzle is typically used in a hydraulic system in which the water is pressurized to about 350 to over 1,000 pounds per square inch. At that pressure a thin, substantially-coherent stream of water is forced out through an orifice that is approximately six one-thousandths of an inch in diameter and against an external impingement pin, which is also about six one-thousandths of an inch in diameter, although it is common for larger size impingement pins to be employed. This creates droplets that are sufficiently small to be essentially unaffected by gravity because of their increased surface area in proportion to their volume. Water droplets of such small dimension evaporate in the air and therefore do not contribute to localized wetting and its consequent disadvantages, such as mildew, mold, and water damage. With the evaporation of each droplet, its heat of vaporization is removed from the ambient air, reducing the ambient air temperature. An array of 200 to 300 of these nozzles can cool a large area, including outdoor areas.
A suitable pin jet nozzle for producing fog is disclosed in U.S. Pat. No. 5,620,142 to Elkas, the disclosure of which is hereby incorporated by reference in its entirety. This patent teaches the use of an orifice member that is prepared from a ruby or sapphire wafer. An orifice is cut into the wafer and then wire polished to a tolerance (as small as 0.0002 inch) which is not possible with other techniques, such as drilling or extrusion. The wafer is then firmly held within a generally cylindrical insert member by standard metalworking techniques to expand a portion of the metal of the insert member over the surface of the orifice member. The insert member is then placed and secured into an orifice outlet of a nozzle body. Subsequently, an impingement pin is installed in alignment with the orifice. Although this fog nozzle was a vast improvement over the prior art, it has been found that the insert can deteriorate under acid cleaning. In addition, there is a possibility that leakage may occur between the mating surfaces of the insert member and the nozzle body. Accordingly, it is desirable to provide a fog nozzle that is less subject to deterioration and leakage than the prior art.
According to one aspect of the invention, a pin jet nozzle for providing an evaporative fog with fluid particles having a diameter of less than fifty micrometers comprises a body member, a disk-shaped orifice member directly secured to the body member, and a pin member mounted to the body member. The body member has upper and lower surfaces, an internal bore for receiving fluid under pressure, and an orifice receiving chamber integrally formed in the upper surface of the body member. The internal bore extends along an axis of the body member from the lower surface toward the upper surface. The orifice receiving chamber is unitary with the body member and in fluid communication with the internal bore. The orifice member is directly secured in the orifice receiving chamber so that an orifice of the orifice member is coaxial with the internal bore. The term xe2x80x9cdisk-shapedxe2x80x9d as used herein means a member that is larger in cross dimension than in thickness, and thus does not necessarily refer to a cylindrical member. The pin member has an impingement pin with an impingement face that is spaced from, and in alignment with, the orifice.
According to a further aspect of the invention, pin jet nozzle for providing an evaporative fog comprises a body member, a disk-shaped orifice member directly secured to the body member, and a pin member mounted to the body member. The body member has upper and lower surfaces, an internal bore for receiving fluid under pressure, with the internal bore extending along an axis of the body member from the lower surface toward the upper surface and including lower, intermediate and upper bore portions, the upper bore portion being smaller in diameter than the intermediate bore portion which is in turn smaller in diameter than the lower bore portion, and an orifice receiving chamber that is integrally formed in the upper surface of the body member. The orifice receiving chamber is unitary with the body member and intersects with the upper bore portion so that the orifice receiving chamber is in fluid communication with the internal bore. The orifice receiving chamber comprises a first annular wall portion that surrounds the orifice member and extends in a first direction from the upper surface of the body member and a second annular wall portion that extends in a second direction toward the axis of the body member from the first wall portion. The orifice member is directly secured in the orifice receiving chamber of the body member and sandwiched between the upper surface and the second wall portion. The orifice member includes an orifice that is coaxial with the internal bore and smaller in diameter than the upper bore portion. The pin member includes an impingement pin with an impingement face that is spaced from, and in alignment with, the orifice.
According to an even further aspect of the invention, a method of forming a pin jet nozzle comprises the steps of: providing a body member with upper and lower surfaces; forming an internal bore in the body member, the internal bore extending along an axis of the body member from the lower surface toward the upper surface; forming an orifice receiving chamber in the upper surface of the body member, the orifice receiving chamber being unitary with the body member and in fluid communication with the internal bore; providing an orifice member with an orifice; securing the orifice member directly in the orifice receiving chamber of the body member so that the orifice is coaxial with the internal bore; and securing a pin member to the body member, the pin member including an impingement pin with an impingement face that is spaced from, and in alignment with, the orifice.